Clinical and Immunohistochemical Characteristics of Pancreatic Neuroendocrine Tumor: Immunohistochemical Analysis of 7 Tumors

ABSTRACT

BACKGROUND: Neuroendocrine tumors of the pancreas are classified according to the endocrine function as insulinomas gastrinomas somatostatinomas, or nonfunctioning tumors. However, the morphologic features are not different from each other. Therefore, we tried to compare correlations among the morphologic features, endocrine function, and the immunohistochemical reaction with specific monoclonal antibodies to the tumors. METHOD: We reviewed the medical records of seven patients with pancreatic neuroendocrine tumors retrospectively, and analysed the clinical manifestations, the methods of diagnosis, the pathological characteristics and the results of surgery. Additionally, we compared the correlation between the clinical manifestations and the expression of immunohistochemical staining by using six different kinds of monoclonal antibodies to each tumor. RESULTS: The seven pancreatic neuroendocrine tumor patients were treated by surgical excision. Four patients had benign insulinomas, two had nonfunctioning malignant tumor and one patient had a benign nonfunctioning tumor associated with stomach cancer. The pattern of immunohistochemical stain of each tumor was not correlate with the clinical manifestations. CONCLUSION: The morphologic study with H & E stain, even with immunohistochemical staining of pancreatic neuroendocrine tumor, cannot support differentiation of the functional diagnoses, such as insulinoma, gastrinoma, somatostatinoma, nonfunctional tumors and so forth.